255 
the Force of fired Gunpowder , 
1793, in his return from Italy; and though I was then absent 
(travelling for the recovery of my health), yet, by my directions, 
he was not only shewn every part of the apparatus made use 
of in these experiments, but several experiments were actually 
repeated in his presence; and he was kind enough to take with 
him to England one half of the barrel which was burst in the 
experiment just mentioned, which at my request he has de- 
posited in the Museum of the Society, and which I flatter 
myself will be looked upon as the most unequivocal proof of 
my discoveries relative to the amazing force of the elastic va° 
pour generated in the combustion of gunpowder. 
When the amazing strength of this barrel is considered, 
and when we consider the smallness of the capacity of its bore, 
it appears almost incredible, that so small a quantity of powder 
as that which was employed in the experiment could burst it 
asunder. 
But without insisting on the testimony of several persons of 
respectable character, who were eye witnesses of the fact, and 
from whom Sir Charles Blagden received a verbal account, 
in detail, of all the circumstances attending the experiment, I 
fancy I may very safely rest my reputation upon the silent 
testimony which this broken instrument will bear in my fa- 
vour; much doubting whether it be in the power of art to burst 
asunder such a mass of solid iron, by any other means than 
those I employed. 
Before I proceed to give an account of my subsequent ex- 
periments upon this subject, I shall stop here for a moment to 
make an estimate, from the known strength of iron, and the 
area of the fracture of the barrel, of the real force employed by 
the elastic vapour to burst it. In a course of experiments upon 
